I just want a snap shot + update

[Capt Slog]

Hi,

I'd like to be able to verify what I think I've seen through my telescope by checking an image against something like the Stelarium ocular view.  I can't take the PC to where the 'scope is, so I'm left with taking a photograph somehow.

I'm looking at the easier to spot clusters at the moment.  The trouble I find is that what I've seen through the eyepiece often looks nothing like what I'm expecting.  I've even made sketches of what i think are the pertinent stars/patterns, but nope, later when i get back to the PC they are completely unrecognisable.  E.g. the Double Cluster, can't think what else it can be just 'there'   and YES I am correcting using the ocular view.  😀

I must stress that I'm not after the beautiful images that I see made on here (but wouldn't object if they were half decent, of course), all I need is a simple reference shot.  I have Nikon DLSR cameras, is the easiest way to buy some sort of adaptor?  I'm looking for cheap here, I just need something that will work for the lowest outlay.  I don't want to buy X and then find I need Y+Z to make it work.

Skywatcher 150, F5 750mm  if that helps.

 

Thanks

Edited January 21, 2021 by Capt Slog

[LordLoki]

Hi Slog,

So if i understand you correctly you are looking through your eyepiece, you see something, and you want an easy way to get a picture of what you see through the eyepiece to then compare it with Stellarium? 

I would recommend to get something like this you can find super cheap versions of it on ebay wish etc as well. Or if you are a fan of DIY do something like this DIY Phone Holder

That way you can use your phone to make a picture directly through your eyepiece  and then you could even upload it to Astrometry.net or Telescopius to get it solved and see what exactly it is you are looking at 

Edit: If you have very steady hands you can try to snap a shot without an adapter as well 

Greets

Marc

Edited December 11, 2020 by LordLoki

[Capt Slog]

Hi Marc,

sadly, my phone looks like this..

and is just adequate for making calls 🤣

The camera in it is sufficient for distinguishing between light and dark  (okay, this is hyperbole, but it isn't good)

I have tried holding it to the eye piece, the result was a black photograph, I couldn't see anything.  I will try again using a terrestrial target in the daylight to see what is happening if anything.

 

However, you have exactly the right idea of what i was after.  I've also tried with my go-pro clone, but don't get anything either.  Since starting the thread, I've done a bit of research (yes, I should have done it first, but learning curves are steep when you don't even know what to ask for)  and i think i might need this...

https://www.ebay.co.uk/itm/1-25-Astronomical-Telescope-Mount-Adapter-T-SLR-Ring-for-Camera-Lens-Black-UK/114480172305?hash=item1aa78ccd11:g:wFwAAOSwnRpfk-J-&var=414676248885

Which might allow me to quickly change over to a nikon instead of the eyepiece.

 

[Erling G-P]

I can see a number of problems with your suggestion about a quick swap of eyepiece with DSLR. 

First is that focus almost certainly will need to be adjusted, as it's unlikely to exactly match the eyepiece. I'm an imager myself, with a DSLR, and use a bright star combined with live view & a Bahtinov mask.  If you haven't got a bright star in your view, focusing will be next to impossible, and so you will have to slew the telescope on to one, and then return to your former object for the image itself.  Depending on how you found it in the first place, that might constitute a problem.

Second is that your field of view with the DSLR may be a lot larger or smaller, depending of what kind of eyepiece you use.

Third is that to register anything on the image, you will often need long exposures of several seconds at the very least, thus needing a tracking mount - preferably a polar aligned EQ type. Can't see in your original post what mount you're using.

Sorry to be a party pooper, but I'm afraid a DSLR is badly suited to make the quick snapshots you're after.

[LordLoki]

Yeah i agree with Erling if you use the camera instead of the eyepiece you will never see the same thing. 

I have never done this myself but i think what you are looking for is eyepiece projection but i am not sure if this gives you exactly the same view but i think it should.

If we would not have such shitty skies i would check if i find mine and test it  but maybe someone else knows if that would give you the result you want.

https://www.amazon.com/Gosky-1-25-Adapter-Nikon-Cameras/dp/B0184WR4OA/ref=sr_1_5?dchild=1&keywords=eyepiece+projection+adapter&qid=1607706359&sr=8-5

PS: its been i while since i saw a phone like that

reminds me of my very first mobile phone

 

[rickwayne]

Respectfully disagree. Plate solving can work with a small number of stars, and the image can be of pretty terrible quality. (I am a world-class expert on astro images of terrible quality.)

So my advice to Capt. Slog:

1. Go ahead and get the T-adaptor. Don't mess with eyepiece projection.
2. In daylight, hold your lensless and adaptor-less bare DSLR up to the empty eyepiece holder of your scope, running live view. Wave it back and forth until you have a rough idea of how far out it has to be to achieve focus.
3. At night, center a bright star or planet in the eyepiece.
4. Replace the eyepiece with the T-adapter and camera. Run the camera at the highest ISO setting that will work, live view again.
5. Rack the focuser until you reach the approximate distance from Step 2, then focus manually. Don't worry about perfect focus.
6. Mark that spot on the focusing tube with tape (if it's further in than the eyepiece focus position), or some other reasonably reproducible method.
7. Shoot various exposure lengths until you find one that gives you at least a handful of visible stars.
8. Put the eyepiece back in, get pointed at your target.
9. Replace with the camera again. Rack to the tape or mark. Shoot the exposure found in Step 7.
10. Profit! (I.e., upload a JPEG to nova.astrometry.net and see exactly where you were pointed.)

Edited December 11, 2020 by rickwayne

[rickwayne]

Note: In Step 2, do not bash your mirror or sensor against the end of the eyepiece tube. Ask me how I know. Also, be sure you're pointed at a really distant object.

Edited December 11, 2020 by rickwayne

[Tiny Clanger]

5 hours ago, Capt Slog said:

Hi,

I'd like to be able to verify what I think I've seen through my telescope by checking an image against something like the Stelarium ocular view.  I can't take the PC to where the 'scope is, so I'm left with taking a photograph somehow.

I'm looking at the easier to spot clusters at the moment.  The trouble I find is that what I've seen through the eyepiece often looks nothing like what I'm expecting.  I've even made sketches of what i think are the pertinent stars/patterns, but nope, later when i get back to the PC they are completely unrecognisable.  E.g. the Double Cluster, can't think what else it can be just 'there'   and YES I am correcting using the ocular view.  😀

I must stress that I'm not after the beautiful images that I see made on here (but wouldn't object if they were half decent, of course), all I need is a simple reference shot.  I have Nikon DLSR cameras, is the easiest way to buy some sort of adaptor?  I'm looking for cheap here, I just need something that will work for the lowest outlay.  I don't want to buy X and then find I need Y+Z to make it work.

Skywatcher 150, F5 750mm  if that helps.

 

Thanks

I have used stellarium ocular view to check I am looking at the right configuration of stars a few times by using my rubbish smartphone camera, but approaching the problem from the opposite direction..

1) on stellarium do ocular view of target (with night view enabled so everything is red , dont want to risk messing up light adaptation)

2)  take a photo  of  the screen , showing the ocular view

3) take 'phone out to 'scope, compare EP view to snap on phone .

Works for me !

Heather

[Capt Slog]

Thanks for the responses, people.

I'm going to try the advice of Rickwayne.  Whilst i respect the opinions of others who say it won't be possible, I reitterate that I only ever wanted an 'image' no matter how poor.  Nor did I want to see exactly the view through the ocular (which I'll admit I might have alluded to that, it's more a case of inaccurate terms if i did).

 

Another confusion for me is why a DSLR would not be able to pick up a half decent image when it has control over shutter and ISO, but the phone camera could!  If they have become that sophisticated I've way out of touch.

I'm going to practice with daylight targets to find the best positions, and also the best camera.  Looking yesterday i realised that i also had a moderately decent olympus bridge-type camera which I know a previous workplace fitted successfully to a microscope.

[M40]

+1 for the t ring and nosepiece. Another thing to be aware of when you bolt your DSLR camera onto your telescope is to turn the brightness of the LCD display up so that you can see what you are looking at in live view. Over time I have accumulated a number of adapters one of which is the eyepiece projection adapter, be aware that not all eyepieces fit in the adapter. One step I took was to buy a Baader Hyperion zoom eyepiece. This together with an adapter which I think comes with the eyepiece, allows the direct connection of the DSLR plus t ring onto the eyepiece. You can then very quickly go from visual to capturing an image. 

Enjoy

[happy-kat]

The book turn left at Orion includes sketches of what the object is expected to look like and how to navigate to finding it.

[Capt Slog]

Initial investigations have been quite encouraging.

The Skywatcher has a removable eyepiece holder, I'd seen this mentioned in a youtube video by the "Astronomy and Nature" channel.  This apparently makes it a whole lot easier using a dslr because it puts the focus in the right place

 

Holding a DSLR to the tube allowed me to use the viewfinder of the camera, and I had to adjust the focus by only fraction of a turn.  The image I see is full frame in the viewfinder, but obviously not the same magnification; what fills the 20mm eyepiece occupies about 1/4 of the frame of the resulting digital image.

It's not my intention to be continually changing this over, maybe an image or two per session, so I think that's doable if I can get the exposures right.

One thing I have just seen however, is that my photograph is corrected in both directions.  That's going to be interesting to sort out!

[Graham Darke]

What about using a flip mirror so you can attach you dslr and eyepiece simultaneously? You can then flip back and forth between eyepiece view and camera. 

[alacant]

29 minutes ago, Graham Darke said:

29 minutes ago, Graham Darke said:

 

 

 

 

Edited December 12, 2020 by alacant

[rickwayne]

Gently, gently. Don't spook him. We'll have him over to the Imaging Dark Side before he knows what hit him :-).

[Capt Slog]

14 hours ago, rickwayne said:

Gently, gently. Don't spook him. We'll have him over to the Imaging Dark Side before he knows what hit him :-).

🥴

[maw lod qan]

16 hours ago, rickwayne said:

Gently, gently. Don't spook him. We'll have him over to the Imaging Dark Side before he knows what hit him :-).

Oh that is so true!

 

Looking at that image on your computer screen of something out there that just seeing has left you speechless is addictive!

Only thing I will tell you is good luck and have fun!

[Capt Slog]

Sadly, my location means that everything will look like it's been photographed through soup.  I can't see the Andromeda galaxy naked-eye, and it's a disappointing smudge through an eyepiece most nights.

 

Edited December 13, 2020 by Capt Slog

[rickwayne]

I feel you, man. I resorted to narrowband imaging because of the light pollution in my neighborhood.

[Capt Slog]

Last night was the first clear night I've had to try to get a an image.

having got the object in the eyepiece, I then unscrewed the eyepiece holder from the telescope and then held the camera without a lens attached over the focus tube.  It sort of locates, but i didn't want any part of the tube to go into the camera, i was also worried about what might happed if a managed to bridge the electrical contacts that are exposed.  I focused through the camera, which wasn't very well.  I took around 25 photos this way, at varying shutter speeds, all at iso1600 (the max on this camera).

The image below is 2 sec, hand held/resting on the focus tube.  After a bit of messing about with brightness and contrast, this is the best I came up with...

 

I know it's not up to much by the standards on here, but I'm very pleased with it 😀.  When i get a better way of holding the camera steadily (and 'flat'), and learn the focus, things might improve.  However,  it allowed me to do what I needed it for, which was identify what I saw against Stelarium.

[michael.h.f.wilkinson]

Good result given the technique used. I would get myself a 2" to T2 threaded adapter for the telescope, add a T2 to DSLR mount adapter so you can attach your DSLR safely, and safe yourself a lot of hassle and worry about damage. They don't cost much

[Capt Slog]

28 minutes ago, michael.h.f.wilkinson said:

I would get myself a 2" to T2 threaded adapter for the telescope, add a T2 to DSLR mount adapter so you can attach your DSLR safely, and safe yourself a lot of hassle and worry about damage. They don't cost much

Something similar is on the way. 

 

[Capt Slog]

An Update.

Amongst the things i had for Christmas were some bits to fasten my camera to the telescope, namely an adaptor set, and a 2x barlow which fits directly to the adaptor OR will take eyepieces.  (There was a nose piece as well, this didn't work well, hence using the barlow)

 

I only had a brief chance to use this after Christmas.  The biggest problem I found with this, predictably, is getting any sort of focus through the camera.  It's just not easy.  The other day though, I had a brainwave.  It's very likely been done before, but i noticed that the difference between "in focus for the camera" and "in focus for my 20mm eye piece" was not far, just a small wind in of the focus.

So I set the scope up in the daylight, and trained it on distant object, the top of the nearby power station at 4.5km.  I attached the camera and got the best focus i could manage, and then swapped the camera for the 20mm lens.  Without adjusting the focus knob, I achieved focus with the eyepiece by just sliding it out a bit, and then measured the gap this gave.  This was 7.9 mm, like this....

 

I then turned a piece of plastic tube to this length in the lathe to make a collar.  This collar then sits on the 20mm EP, I focus with that, and then change the EP for the camera.  The result isn't going to spot on for certain but I'm hoping it should give me my 'snap shot' capability.  I can focus and change from EP to camera quickly and easily.

The collar isn't in the correct place on the above pic, obviously.  It will slide up to the existing stop.  If it works, I might make something nicer.